1. Field of the Invention
This invention relates generally to sea water batteries utilizing electrochemically active material such as lead chloride, cuprous chloride or a lead chloride/cuprous chloride mixture as the cathode electrode material, and more specifically relates to a method of forming cathode electrodes from such materials and the electrode structures so formed.
2. Description of the Prior Art
Sea water batteries utilize sea water as the electrolyte, metals such as aluminum or magnesium as the anode and solid insoluble chlorides as the cathode. A typical combination is silver chloride as the cathode and, for example, magnesium as the anode.
Although silver chloride gives higher voltages than lead chloride the latter is preferred from the viewpoint of cost. However, conventionally formed lead chloride electrodes suffer from the disadvantage of fragility, both initially and during operation. The conventional technique for forming lead chloride electrodes is to mix lead chloride powder with a binder and with carbon or a similar electrically conducting material. The powderous mixture is then compacted under high pressure around both sides of a metallic conductor, which typically comprises copper or nickel gauze, perforated sheet or expanded metal.
The presence of the required conducting material and binding agent in the electrode structure decreases the concentration of active material in the electrode. Since the efficiency of the electrode, and hence the cell wherein it is employed, is largely dependent upon the amount of active material contained in the given volume, the presence of other substances such as conducting materials and binders clearly reduces the electrical efficiency of the structure.